Method and apparatus for heat exchange



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ATOE/VEY W 355 c. "I". SORENSEN METHOD AND APPARATUS FQR- HEAT EXCHANGE2 Sheets-Sheet 1 Original Filed Nov. 13, 1946 79 'larewez fiarezzs'eaWWW &

6. T. soRENsEN METHOD AND APPARATUS FOR HEAT EXCHANGE Original Fi ledNov. 15, 1946 2 Sheets-Sheet 2 IN VEN TOR.

Unite States Patent MEIR-IUD AND AFPARATUS FOR HEAT EXCHANGE Clarence T.Sorensen, Lakewood, Ohio, assignor of twelve and one-half per cent to L.S. McLeod, Evanston, 11]., ten per cent to W. Kendall, (Ileveland, Ohio,five per cent to P. W. Lewis, and live per cent to W. W. Lorch, both ofhit. Louis, Mo.

Original appiication November 13, 1946 Serial No. 799,519, new PatentNo. 2,525,431, dated October 1.0, 195i). Divided and this applicationNovember 18, 1949, Serial No. 131,643

9 Claims. (#Cl. 257--1) This invention relates to improvements inabsorption refrigeration systems and processes. The present applicationis a. division of my application 709,519 filed November 13, 1946, nowPatent 2,525,431, granted October 10, 1950, as a continuation in part ofmy application 417,107 entitled Absorption Refrigeration Sys tems andProcesses and filed October 30, 1941, now abandoned.

It is an object of the invention to facilitate the action of a heatexchanger such as a condensing radiator and to make it more efficientand enable heat exchange to proceed more rapidly with less radiatingsurface in a device of the present character by circulating a heat exchange fluid, using arriving fluids to maintain the heat exchange fluidin circulation, and forcing the arriving fluids into and through theheat exchange fluid whereby, in the present device, the liquid absorbsheat from the gases during the heat rejecting cycle and delivers offsuch heat by radiation during intervals when no gases are being suppliedto the condenser.

In the drawings:

Fig. 1 is a diagrammatic perspective showing the circuit connectionsbetween the component units of a refrigerating mechanism embodying myinvention.

Figs. 2 is a view on a reduced scale fragmentarily illustrated indiagrammatic perspective circuit connections similar to those of Fig. 1but employing modified condensing radiator arrangements.

Fig. 3 is a view in plan of a modified condenser arrangement such as isillustrated in Fig. 2.

Fig. 4 is an enlarged detail view in vertical section through a portionof the condenser shown in Fig. 3.

Fig. 5 is a view similar to Fig. 4 taken on a different section throughthe device of Fig. 3.

Fig. 6 is a view in side elevation through a different embodiment of thetype of condenser radiator shown in Fig. 3.

Fig. 7 is a fragmentary detail view taken in section on an enlargedscale through a portion of the condenser receiver shown in Fig. 2.

Like parts are identified by the same reference characters throughoutthe several views.

The boiler or generator 24) of the refrigeration system disclosed in mypatent above identified may comprise a substantially cylindrical tanklying on its side and peripherally flanged to facilitate heat exchange.Any desired heat may be provided, as exemplified by a burner 21 turnedon and off by an automatic valve diagrammatically illustrated at 22, thecontrol for which may be as disclosed in Dillman Patent 2,224,099. Anyother controls, manual or automatic, may be substituted so far as thepresent invention is concerned.

The strong liquid or saturated absorbent may fill the generatorsubstantially to the level indicated at A, at which level the thermostat23 forming a part of the con trol system will be covered. The lowestlevel which the weak liquid absorbent will reach in the generator isPatented May 31, 1955 represented by the line at B in Fig. 1, at whichlevel the thermostat 23 will be exposed above the level of the liquid.

Between the level of the bottom of the generator and the levelrepresented by the line B, I provide a single or multiple coolingradiator at 24 in an absorbent cooling loop which provides a closedcircuit between the radiator and the absorbent liquid in the generator.The hot liquid outlet from the generator is provided from the high endof an inclined pipe 25 which projects from both ends of the generator,as best shown in Fig. 1. Pipe 26 provides a trap at 2'7 and extendsthence to the radiator 24. If a duplex cooling radiator is provided asspecifically illustrated in Fig. 1, a separate pipe 23 may issue fromapproximately the same level in the generator to flow in parallelthrough the cooling radiator 24. From the discharge portion 29 of thesingle or duplex cooling radiator coils issues a return pipe 30 providedat 31 with a trap and returning in an upward direction into pipe 25 atits lower end.

Approximately the lower one half of pipe 25 is cut away within thegenerator or boiler 2d, leaving at 25 within the boiler an invertedsemi-tubular trough upwardly inclined but maintained at all times belowthe level of absorbent in the generator. Except for the traps 27 and 31,all portions of the circulatory loop, including cooling radiator 24, arehigher than the bottom of the generator and lower than the minimum levelof absorb: ent therein.

Generator Z6- is provided with an outlet at 32 for gaseous refrigerantdriven from the absorbent during the heating portion of the cycle. Theoutlet pipe 32 leads to a U-tube 33, the ends of which enter separatefloat chambers 34.

From the chambers 34, pipes 46 and 47 lead with a substantial upwardpitch to the lower flights of rectifying radiators 48 and 49respectively. The radiators are preferably identical; the runs of pipeat 46 and 4-7 are substantially identical, it being desired that pipe 46and radiator 48 be in balance from a heat exchange standpoint with pipe47 and radiator 49. Referigerant evaporated in the generator or boiler20 passing upwardly through the respective valve sets 44 and 45, isaccompanied by a certain amount of absorbent liquid which is unavoidablyentrained therewith. The heat exchange capacity of the rectifyingradiators 48 and 49 is so determined with reference to normal conditionsto which the device is exposed in use, that no appreciable quantities ofrefrigerant will be condensed in rectifying radiators 48 and 49 butsubstantially all of the absorbent will be condensed therein and willflow backwardly through the radiators and the pipes 46 and 47 to thestill or generator at 20.

Immediately beneath the pair of rectifying radiators 48 and 49 (in thepreferred physical disposition of the parts), I provide a condenserradiator 50 of much larger capacity which may have added sections at 51and 52 which are so disposed as to facilitate the flow through them ofthe coldest air circulating in the flue in which the radiator assemblyis located. The pipe 53 discharging from the top of rectifying radiator49, enters the top of condenser radiator 50, such radiator comprising afinned tube which is continuous in a series of convolutions downwardlyto its lower end. At its lower end the tube which comprises condenserradiator 5'1) may communicate with a radiator receiver 54, the use ofwhich is optional since the refrigerant condensed in radiator 50 may, ifdesired, be discharged directly from the con denser radiator withoutfirst being accumulated in the receiving tank 54.

The cooling radiator 24 and the condenser radiators 50, 51, 52,alternate in giving oif heat at different periods of the cycle so thatthe heat given off by one in no way affects the heat radiating capacityof the other. Together they are practically continuously rejecting heat,thereby rfrliaintaining a substantially continuous air current up theWhether the condensed refrigerant is taken from accumulator 54 ordirectly from the condensing radiator section 52, there will in eithercase be a well provided at 55 from which conduit 56 leads upwardly to anupper portion of the evaporator receiver. The bulb 59 of the controlthermostat may be located in receiver 16 if desired.

From the bottom of the evaporator tank 16 open the headers 62 and 63 ofthe evaporator 15. U-shaped tubes 60, 61 extend in communication witheach of the headers 62 and 63. Each header, however, is extendeddownwardly below the bottom of tube 61 and provided with a tube 65 whichfollows a U-shaped pattern but extends rearwardly and upwardly at 66 andthence horizontally at 67 into a standpipe 68 at an intermediate point.The top of the standpipe is placed in comunication by means of tube 69with the top of the receiver 16.

From the bottom of the well which is provided by the closed lower end ofstand-pipe 68, leads a conduit 75 which may conveniently be spaced fromthe extreme lower end of the chamber by beveling its end as shown inFig. 1. This conduit issues from the top of the charnher and thenceextends at 76 into an enlarged duct 77, the lower end of which isdrained by pipe 78 leading through trap 79 into the lower end of pipe25, whereby a return connection is provided for liquid absorbent.

Gaseous refrigerant evaporating in the evaporator tubes 60,- 61, headers62 and 63, pipes 60 and 61, and in the receiver 16, is returned from thetop of the receiver 16 through pipe 80 down to one of the lowermostportions of the circuit near the bottom of the trap 31 in the portion ofthe absorbent circulating loop through which the cooled absorbent isreturned from cooling radiator 24 to the generator or still 20. Thepoint of connection is designated at K in Fig. 1. The pressure balancingconnection from conduit 46 through rectifying radiator 48 to theevaporator is made by means of tube 82 which leads from the top ofradiator 48 into the refrigerant return pipe 80, although any otherconnection at a high level to the upper end of the evaporator oradjusting portions of the system, would serve equally well.

'The various traps should desirably be proportioned as follows:

- The column of liquid in the tube 75 in the well 68 of' the evaporator,as measured from the lower end of the tube 75 to the level of liquid inthe evaporator, should at all times be less than the distance betweenthe bottom of trap 79 vertically to the level A (the maximum level ofliquid in the boiler generator 20). In practice, 1 prefer that theextent of trap 79 below the maximum liquid level in the generator beapproximately 1%. inches greater than the distance from the bottom oftube 75 'to the maximum level of refrigerant in the evaporator.

On the other hand, the distance from the bottom of trap 79 to theminimum level B of liquid in the boilergenerator shall be less than thedistance from thebottom of tube 75 to the maximum level of liquid in theevapora-' tor receiver 16.

The vertical distance of point K below the level A which represents themaximum level of liquid in the boiler-generator is also less (preferablyby about 1 /2 inches) than the length of pipe 75 from the bottom thereofto the maximum level of liquid in the evaporator receiver 16.

The device operates as follows:

As generally described in Dillman Patent 2,224,099, the heating cycle isinitiated by heating the thermostat bulb 59 after such bulb is exposedby the receding level of liquid in the evaporator receiver 16 as therefrigerant therein becomes evaporated for cooling purposes, This opensthe automatic valve at 22 supplying fuel to burner 21 and the flameignited by a suitable pilot (not shown) heats the boiler generator orstill 20.

Due to the re-absorption of refrigerant by the absorbent in the still20, the height of liquid in the still at the commen'cement of the cyclewill be represented approximately by the line A (Fig. 1). While it isbroadly immaterial what refrigerant and what absorbent are used, it mayfor the purposes of this disclosure, be assumed that the absorbent isordinary water and the refrigerant is ammonia gas.

The heat will expel ammonia gas from the strong liquor in the generator25), and the ammonia gas, together with such water vapor as isunavoidably entrained therewith, will issue from the generator throughpipe 32 and enter the U-tube 33, escaping therefrom through valves 36into the chambers 34 to the valve sets 44 and 45.

As above noted, the heat rejecting capacity of rectifying radiators 48and 49 is so chosen as to condense most of the Water vapor Withoutcondensing the ammonia vapor. The condensate will flow back through pipe46 and pipe 47 to chambers 34, raising the floats 35 in such chambersand thereby lifting the check valves 36 from their seats to permit thereturn of the condensate to the generator. Meantime the principaldelivery of refrigerant vapor is occurring through the condensingradiator 50, 51, 52, and the condensed refrigerant is being received andstored in the receiver 54 (or in the bottom of the condenser section 52,or both). Some substantial portion of the condensed refrigerant would bedelivered directly to the evaporator at this point but for theequalization of pressures throughout the system achieved through pipe 46and balancing radiator 48 and capillary connection 82 to the top of thesystem.

The amount of refrigerant delivered to the top of the system will benegligible because the refrigerant so delivered tends to remain gaseouswhereas the refrigerant delivered through pipe 47 and rectifyingradiator 49 is condensed in radiator condenser section 5t 51, 52, and,occupying considerably less volume in its condensed state, it makes roomfor the constant accession of further supplies of gaseous refrigerantthrough this portion of the system. Condensation is, of course, achievedby a combination of high pressure and heat rejection in the condenserradiator sections.

The direct communication of pressure through the balancing pipe e6,rectifying radiator 49, and communicating pipe 82, likewise prevents theabsorbent from being forced backwardly up from the generator througheither of the return'ducts 79 or 80.

So far as the absorption liquid is concerned, it will be apparent thatno convection currents will be established between the generator 20 andthe loop cooling radiator 24 for the reason that the absorbent issubstantially at the same level throughout the circuit comprising thegenerator, the loops, and radiator 24. Consequently the absorbent willremain substantially non-circulatory in the loop system during theheating phase of the cycle.

-When the evaporation has progressed to the point where the absorbent ingenerator 26 has dropped to the level indicated at B, thereby partiallyor Wholly exposing the thermostatic bulb 23 above the liquid level, thecontrols will function to cut off the supply of fuel to the burner 21,thus initiating the cooling phase. Air Will continue to rise through theheated flue 86 about the tins of the generator 29, rapidly cooling thegenerator and thereby decreasing the pressures existing in thegenerator. Pressures will remain high in the rectifying and condensingradiators 48, 49, 5t), 51, 52, because the check valve chambers 34,prevent the maximum pressure achieved during the heating phase frombecoming relieved back to the generator. However, the low pressures nowexisting in the generator will eventually result in at least partialreductionof pressures at the evapo- 76'77-78 and 80 affording freecomrator, the pipes riunication between the generator and therefrigerator save only for the seals provided at 31 and 79.

As soon as the evaporator pressure drops below the pressure in thecondenser radiators, the entire supply of liquid refrigerant accumulatedin the condenser radiators and the radiator receiver 541, will bedelivered by the existing pressure differential from the well throughthe pipe to the evaporator receiver 16 which will be substantiallyfilled by the liquid refrigerant thus transferred. Once the transfer ofliquid refrigerant commences, it will be accelerated by heat rejectedfrom the radiator 24 as hereinafter described, tending to raise thetemperature of the refrigrant in the accumulator 54, thereby increasingthe pressure at this point in the system.

As soon as the liquid refrigerator is delivered to the evaporator itwill normally commence to evaporate therein. The resulting refrigerantvapor passing through the return pipe 8h to the point K in the trap 31,will bubble into the weak liquor standing in trap 31 and will rise inthe return side of trap 31 toward the generator. This will exert a verysubstantial pumping action initiating the rapid circulation of absorbentthrough the loop system, including loop cooling radiator 24. Since theweak liquor into which the returning vapor is delivered at K is air adycool, re-absorption will immediately commence, and this absorption willcontinue as the refrigrant bubbles move with the weak liquor in thereturning side of the loop toward the generator. If the capacity ofradiator 24 is approximately equal to the capacity of the generator atthis point in the cycle, this circulation will ultimately completelyreplace the hot weak liquor in the generator with cool weak liquor fromthe cooling radiator, leaving the generator filled with cool liquor andleaving substantially all of the warmer weak liquor in the radiatorwhere it may speedily give off its heat.

This heat will be delivered to convection currents of air rising in theflue and these currents will tend to reheat, to a material degree, theaccumulator 54, thereby raising the pressure of the refrigerant trappedin this accumulator and accelerating the delivery of the remainder ofsuch refrigerant toward the evaporator receiver 16 as above described.

in the meantime such bubbles as are still entrained unabsorbed in theweak liquor entering pipe 25 at its lower end from loop duct 36, are notreleased in the generator to bubble noisely to the surface. The weakliquor itself is freely discharged into the generator by reason of thefact that the whole lower half of pipe 25 is cut away. The remainingupper half 25 of pipe 25 serves, however, as an inclined and invertedtrough which retains the bubbles in full contact with theweak liquid inthe generator and in constantly shifting communication therewith as thebubbles slowly rise by reason of the inclination of the inverted trough.Ordinarily all such gases will be completely absorbed in traversing thelength of the inverted trough section 25 of pipe 25', but should anysuch bubbles fail to be absorbed they are still held against release andreturned through pipe 26 to the cooling radiator 2 There are importantadvantages in delivering the gaseous refrigerant at K into the returnside of the loop circuit where it will act upon weak liquor which hasalready been cooled.

The absorbent, in liquid form, is materially heavier than therefrigerant, and insofar as any absorbentis condensed or passed inliquid form into the evaporator, it will tend to settle to the lowestpoint in the evaporator system and will therefore be collected in tubes65' which leads from the lower ends of headers 62, 63. The problem ofreturning such liquid absorbent from the evaporator to the generatorwithout completely emptying the evaporator of liquid refrigerant issolved by the system disclosed in the following manner.

At that portion of the cycle when the initial cooling of the ge eratorresults in delivery of liquid refrigerant from the condenser to theevaporator receiver, the presstands therein below the level of suredifferential created by the influx of liquid refrigerant into the top ofthe receiver forces out of pipes 65 of the evaporator a substantial partof their entire liquid contents, these being discharged into thestand-pipe 68 midway of the height thereof through duct 6'7. Thisoperation, therefore, results in delivering into the stand-pipe 63 allof the liquid absorbent which has collected in the evaporator. Theproportions of the parts are so determined as to make such of thusdelivering to the, standpipe all of the liquid absorbent even thoughsome liquid refrigerant may also be similarly delivered to thestandpipe.

During the entire evaporation phase of the cycle in which the liquidrefrigerant is evaporating in the evaporator and the gas is returning tothe generator as above described, such liquid absorbent will remain inthe well at the bottom of stand-pipe 63. At the initiation of the nextheating phase when the burner 21 is again lighted and gas is againexpelled from the absorbent in the gen? erator, the initial pressuredifferential developed in the generator will be communicated immediatelythrough the balancing leg of U-tube 33 and through the valve set 44,pipe 446, rectifying radiator 48 and duct 82 to the top of theevaporator where it will subject to pressure the upper surface of theliquid trapped in the Well at the bottom of stand-pipe 63. This pressurewill exceed the pressure in the tube 75 which extends downwardly to thebottom of the Well for the reason that any back pressure tending to becommunicated to tube '75 through trap 79 and pipe 78 is resisted by thehead of liquid raised in pipe 73 from trap 79. The result is toestablish a pressure differential between the stand-pipe 68 and the tube75' therein contained, which results in forcing the accumulated liquidfrom the bottom of the stand-pipe upwardly through tube 75' into tube 76and thence downwardly through the enlarged pipe 77. The cross section ofpipe 77 is sufi'iciently large with respect to the cross section of tube76 and tube 75 so that the liquid descending; through pipe 77 cannotsiphon all of the liquid from the evaporator but can only draw from thestand-pipe 68 such liquid as tube 67. It will be noted in Fig. 1 thatthe well 65 is enlarged from this point downwardly, this being one ofseveral possible means of breaking any siphon action at that point,whereby to prevent any vacuum from being pulled on the upper end of thestand-pipe. As a result, such liquid absorbent as is in the well at thebottom of the stand-pipe is returned, with perhaps a small quantity ofliquid refrigerant likewise standing below the level of tube 67 in thestand-pipe. Such remaining body of liquid refrigerant as may have beenleft in the evaporator tubes 60, 61, 62, 63, 65 at the commencement ofthe cycle remains undisturbed, as tube 69 balances pressure between tube68 and receiver 116 to prevent liquid refrigerant from being siphonedback to the generator with purged absorbent.

Thus, by a series of pressure differentials successively established atdifierent intervals in the cycle, I am able.

progressively to segregate and return absorbent which reaches theevaporator, without inefliciently returning for re-absorption andre-evaporation any substantial quantities of refrigerant which may existin liquid form in the evaporator.

By reason of its intermittent cycling as above described, my improvedrefrigeration system develops pressure differentials which are entirelyadequate for the alternate.

evaporation or condensation of refrigerant without re quiring theexcessively high pressures which are necessary in the continuous typeabsorption refrigerators. The

resulting action is very positive as compared to the action of otherabsorption systems of the intermittent type. The means of returningliquid absorbent as above described avoids the delivery of anyappreciable quantity. of hot gases into the evaporator and at the sametime so successfully purges the system with a minimum of refrigerantwaste that the hold-over capacity of the brine tank 72 is adequate toprevent defrosting of the quick freezing shelves and ice trays duringthe heating phase of the cycle.

I have found that the condensing radiators may be made more efficient torequire less material and less space and to operate on a new principleif they embody the heat exchange feature which is the specific subjectof this application. Each of the rectifying radiators 480, 490, whichserve as modified embodiments of the previously described rectifyingradiators 48 and 49, is preferably made in the manner clearly shown inFig. 2 and Fig. 3 to comprise a closed circulatory loop 96 provided withthe usual radiating fins and into which the mixed gases delivered fromthe check and float valve sets are delivered through circulatoryflow-inducing nozzles 91 (Fig. 3). Drain pipes 92, 930 connected withthe respective circulatory loops maintain normal liquid levels asindicated at F in Fig. 4, below which the nozzle 91 is disposed. Thusthe gas issuing from the nozzle 91 engages and entrains the liquid inthe circulatory loop 94 to effect circulatory movement thereof aroundthe loop whereby fresh liquid is constantly being presented to the gasissuing from the nozzle. At intervals about the loop, I may providebaflies 93 which extend downwardly below liquid level to force any gaswhich has separated in the upper part of the loop to re-enter the liquidin order to pass the baffle. I provide outlets 94, 95 from therespective loops 90, communicating with the capillary pressure balancingtube at 82 and outlet 95 communicating with the more u conventionalcondensing radiator 5%. just beyond each of these outlet pipes 94, $5, Iprovide a much deeper baflie 97 which provides a trap to keep the gasesfrom short circuiting the loop between the inlet and the gas outlettherefrom.

The drain pipes 92 and 93d carry back to the respective valve sets 44,45 the absorbent liquid condensing in the rectifying loop condensers 4%,4%. These are made desirable for the reason that the nozzles 91preferably enter from above, as shown, whereby separate draining meansfor returning the weak liquor is appropriate.

Fig. 6 simply shows an alternative arrangement using a loop 900 which isarranged vertically instead of horizontally. The nozzle 91% entersaxially of the top leg of the loop. The return pipe 920 opens from theupper part of the top leg of the loop and the several bafiles 93 are alllocated in the top leg of the loop. The bottom leg of the loop replacesthe special baflle 97 used in the previously described embodiment toprevent gases from bypassing the several baffles 93 en route to the gasdischarge pipe 94.

The accumulator 54 need not necessarily comprise a tank as shown in Fig.1, but may comprise a loop identical with those shown in Figs. 2 or 5except that the baffles are omitted. Fig. 7 shows a detail of the mannerin which the sump 550 connects to the circulatory loop 540.

In these various circulatory loop type condensers, I take advantage ofthe fact that the gas to be condensed is arriving intermittently. Duringthe interval when no gas is being delivered to the condensers, the finswith which the loop tubes are provided continue to reject heat from theliquid trapped in the loop. Thus, by the time gas is again admitted, thetrapped liquid is thoroughly cooled and, as the gas entrains the liquidat the nozzle, thorough admixture is effected and a large and constantlychanging liquid surface is presented to the gases to assist in thecooling and condensation thereof. The liquid gives suflicient additionalsurface to compensate for a greatly decreased length of condenser tubeand, at the same time, causes the newly arrived gaseous refrigerant tocondense very expeditiously.

Otherwise the modified apparatus embodying any one or more of theseveral alternative embodiments illustrated operates substantially asabove described.

The apparatus and method disclosed in connection with Figs. 2 to 7 areadaptable for heating or cooling a variety of fluids (either gaseous orliquid) through direct contact with an intermediary fluid which isimmiscible with the fluid to be heated or cooled and deriving motionfrom said last mentioned fluid for heat exchange by conduction andconvection. Obviously, I do not mean that the two fluids involved mustbe wholly immiscible, for, in the present case, a certain amount of thegaseous refrigerant will either condense to a liquid and mix with theliquid which is in circulation, or will be dissolved in the circulatingliquid. However, it suflices that the fluid to be cooled may beseparated by gravity or otherwise from the heat exchange fluid, allowingthe heat exchange fluid to give up its heat while circulating to anotherpart of its circuitous path.

I claim:

1. A method of heat exchange with a first fluid confined for circulationin a predetermined closed path which comprises introducing andcommingling with the first fluid, a second fluid with which it ismaterially immiscible, circulating both fluids together along a portionof said closed path, separating said fluids after heat exchange hasoccurred between them, moving the said second fluid in a closed circuitupon which it is returned to said path for further commingling with thefirst fluid, and restoring the first fluid toward its originaltemperature by subjecting it to additional heat exchange after saidseparation and during movement in said closed circuit.

2. The method of claim 1 in which the second fluid is injectedintermittently into the first fluid.

3. The method of claim 2 in which the first fluid is subjectedsubstantially constantly to heat exchange with a third fluid about thetube irrespective of injection of the second fluid.

4. A method of heat exchange which comprises circulating twosubstantially immiscible fluids in closed circuits having a commonbranch in which said fluids circulate in the same direction in contactfor direct heat exchange, separating said fluids after they havetraversed said common branch, and raising the temperature of one fluidand lowering the temperature of the other during their circulation inother portions of their respective circuits.

5. A heat exchange device comprising a closed loop tube, a heat exchangefluid confined for circulation in said tube, means for introducing asecond fluid into the tube and effecting circulation thereof in the samedirection as the heat exchange fluid for direct heat exchange with theheat exchange fluid as well as with the tube, said heat exchange fluidbeing at least materially immiscible with said second fluid, and meansfor the segregated delivery of the second fluid from the tube, leavingthe heat exchange fluid therein.

6. The device of claim 5 in which the means for introducing the secondfluid comprises an injection nozzle directed along the path ofcirculation of the heat exchange fluid in the tube and through whichnozzle the second fluid is introduced into said tube, whereby to entrainthe heat exchange fluid and induce circulation in said tube.

7. The device of claim 5 in which the closed loop tube is horizontallydisposed and the circulatory movement of the liquid is generallyhorizontal.

8. The device of claim 5 in which the closed loop tube is verticallydisposed and the circulatory movement of the liquid is in a generallyvertical plane.

9. The device of claim 5 in which the closed loop tube is provided withbaffle means between the introducing means and the delivery means forprecluding fluid separation from said liquid during said heat exchange.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Baker June 19, 1900 Block July 2, 1918 VonPlaten et a1. Dec. 4, 1928 Copeman Nov. 15, 1932 10 Keith July 18, 1933Kritzer et a1. Ian. 26, 1937 Ullstrand Nov. 14, 1939 Kogel Apr. 1, 1941FOREIGN PATENTS Great Britain Oct. 15, 1925

